The most effective measure to prevent many diseases among animals and/or humans is the mass immunization with vaccines. Needle-free injectors have been used to accomplish this task. The traditional needle-free injectors comprise the basic design, a housing with an inner power unit, a medication unit, and a nozzle. The power unit pumps the medication into an under-plunger cavity of the medication unit chamber and expels the medication through the nozzle.
With the use of a typical jet injector, there exists the possibility of infection transfer from one subject to another by means of fluids (blood, lymph, medication) reflected from the skin surface during injection (“back splash”) that may get on the nozzle and be transferred from one patient to the next. Further, in the injection stage, the contaminated matter can be transferred through the nozzle to inside the injector such as, for example, into the cavity and be transmitted to a new patient through a new cap and nozzle.
Accordingly, there is a need in the art of needle-free injection devices to solve the problem of cross-contamination during mass vaccinations. More particularly, there is a need for a protector designed for the nozzle head of needle-free injectors, which halts “back splash” contamination, and which is low enough in cost to ensure its practical application as a disposable unit even for mass vaccinations.